PlasticBOND

News

27.05.2025 | Events
Enthusiasm for technology – A successful Mechanical Engineering Day in Aachen

On Saturday, 24 May 2025, the Faculty of Mechanical Engineering at RWTH Aachen University opened its doors for the Mechanical Engineering Day. The event on the Melaten campus offered visitors a comprehensive insight into the diversity and innovative strength

read more

Digitalisation methods for optimising the sustainability in plastic material cycles

The percentage of recycled materials in packaging required by EU regulations currently poses challenges for plastics processors, as the material properties of recycled materials often differ from virgin materials. In order to improve the sustainability of plastic packaging, the PlasticBOND project pursued an interdisciplinary approach focussing on three areas: Studying the increased use of recyclates in packaging while ensuring recyclability; developing an evaluation model to assess environmental sustainability; and developing a platform-based information system for the exchange of relevant sustainability data.

To this end, the material technology possibilities and challenges in plastics processing were combined with the ecological assessment of plastic packaging. A digital cooperation network was developed as the basis for the exchange of the necessary sustainability data along the entire value chain. Together with partners from research and industry (Manufacturing Technology Institute of RWTH Aachen University (MTI), Arburg GmbH + Co KG, Brückner Maschinenbau GmbH, Carbon Minds GmbH, Henkel AG & Co KGaA, Interzero Circular Solutions Germany GmbH, Pöppelmann GmbH & Co KG Kunststoff-Werkzeugbau, Reifenhäuser GmbH & Co KG Maschinenfabrik, Reifenhäuser Blown Film GmbH), a demonstrator made of a PE film laminate with an injection-molded PE spout was developed (Fig. 1) and manufactured. A PCR proportion of more than 60 % was achieved. In order to meet the challenges in recyclate processing, extensive process and material analyses were carried out at IKV in both injection molding and extrusion.

Plastic-Bond-3 — Fig. 1: Blown film made from recyclate with gels (left) and illustration of frequently identified gels (right)

In the field of injection molding, IKV dealt with process engineering issues relating to the drying and ageing of recyclates, mixing behaviour with virgin material and seasonal fluctuations. Both process stability and component quality were evaluated. The combination of recyclates with virgin material in particular offers great potential for increasing recyclate usage rates in the short term. IKV therefore analyzed the properties of such mixtures of recyclate and virgin material for PE and PP and investigated their behaviour in the injection moulding process. The rheological, physical, mechanical and morphological properties of different PCR material qualities were evaluated and correlated with conventional parameters. The influence on the injection molding process was analyzed so that recommendations for the processing of PCR materials could be derived.

The Extrusion department investigated process engineering and analytical issues relating to the composition and ageing of recyclates, the reduction of specks and seasonal fluctuations that are relevant to film extrusion. The effects of different recyclates on the process capability and functional properties of films were evaluated. The challenge in the film extrusion of commercially available recyclates is in particular the formation of specks, which has a negative effect on the extrusion process (e.g. tearing of the film web) and the possibilities of further processing (e.g. printing, laminating), as well as on the mechanical properties.

Plastic-Bond-2 — Fig. 2: Demonstrator packaging made from a PE film laminate with an injection-moulded PE spout

Examples of specks in a blown film are shown in Figure 1. Studies have shown that around 30% of the gels analyzed are sharp-edged, cross-linked polyethylene-based particles. The composition of the recyclates in particular, which may contain PP components in PE, compatibilisers or stabilisers, for example, has a major influence on the formation of specks. It was therefore identified as a starting point for the development of recyclable material compounds.

In order to further investigate the ageing mechanisms of typical film compounds, recyclates were examined using high-temperature gel permeation chromatography (HT-GPC). The properties of various PCR material qualities were evaluated in order to classify the recyclability of film compounds. In addition, the influence on the blown film process was analyzed and recommendations for the processing of PCR materials were derived.